My fifthwheel was installed with improper lag bolts, causing frame flex issues. I lost my roof going down the highway last year, pass-through storage compartment doors coming open during transit. Along with that, interior damage became apparent early on after the purchase of the RV, indicating a much greater problem than anticipated. Grand Design sent out an SRT to repair my unit; however, they failed to pull the pylon down off the front of the unit to inspect the frame welds. I may have an impending disaster going down the roadway in the future. All but one lag bolt was being held in under tension. The unit could have become detached from the tow vehicle, and the safety braking mechanism likely wouldn’t have engaged. If my roof came completely off, or items would have fallen out of the pass-through compartments, this could have easily caused a major accident leading to fatalities on the highway.